TH 


AN  ORDINANCE 

FORj 

CONSTRUCTION  OF  CHIMNEYS 

Suitable  for  Use  in  Cities 
and  Towns  of  Any  Size 


OR  AS  A 


State  Law   ,%  ;   -  •• 


Recommended  by  the 

NATIONAL  BOARD  OF  FIRE  UNDERWRITERS 
COMMITTEE  ON  CONSTRUCTION  OF  BUILDINGS 

SECOND  EDITION,  REVISED 

1921 


Foreword 


THE  average  annual  loss  due  to  defective  chimneys  in  the  United 
States  for  the  years  1916-19,  inclusive,  and  reported  by  the  Actuarial 
Bureau  to  the  National  Board  of  Fire  Underwriters  was  $11,898,000. 
All  losses  were  not  reported  and  it  is  conservatively  estimated  that  the 
complete  actual  loss  was  25  per  cent,  larger,  thus  making  an  approximate 
total  loss  per  year  of  $14,872,000.    The  number  of  lives  sacrificed  in  the 
average  23,000  fires  which  produced  this  annual  property  loss  is  not  known, 
but  is  unquestionably  large. 

Since  fires  from  this  cause  are  classed  as  "strictly  preventable,"  it 
should  need  no  further  argument  to  justify  the  promulgation  of  this 
Ordinance,  which  is  suitable  for  adoption  by  a  town  of  any  size,  or  for 
enactment  as  a  state  law.  The  latter  form  would  be  the  most  effective. 

Conservation  of  our  national  resources  is  the  demand  of  the  hour. 
It  is,  therefore,  the  duty  of  all  state  and  municipal  authorities'  to  use 
their  best  endeavors  to  stop  this  great  needless  waste.  The  enforcement 
of  a  law  requiring  safe,  smoke-tight  construction  of  chimneys  of  ample 
size  and  height  would  be  a  sure  means  of  accomplishing  an  immense 
saving  in  life  and  property  as  well  as  materially  increasing  home  comforts. 

Defective  chimney  fires  would  practically  disappear  if  this  Ordinance 
were  generally  enforced,  and  since  the  additional  cost  of  the  construction 
herein  recommended  as  compared  with  ordinary  practice  would  seldom 
exceed  $10  to  $15  per  chimney,  the  requirement  would  not  be  burdensome. 
The  increased  expense  would  be  returned  many  fold  due  to  saving  of  life 
and  property  and  the  efficient  use  of  fuel. 

The  following  organizations  have  reviewed  this  Ordinance  and  ap- 
proved it  as  here  presented.  We  desire  to  express  our  appreciation  for 
helpful  assistance  rendered  by  several  of  these : 

American  Institute  of  Architects, 

American  Society  of  Heating  and  Ventilating  Engineers, 
Associated  Tile  Manufacturers, 
Clay  Products  Association, 
Common  Brick  Manufacturers  Association, 
Eastern  Clay  Products  Association, 

National    Boiler    and    Radiator    Manufacturers    Association, 
National  Fire  Protection  Association, 
National  Brick  Manufacturers  Association, 
National  Lime  Association — Eastern  Bureau, 
National  Lumber  Manufacturer's  Association, 
National  Warm  Air  Heating  and  Ventilating  Association, 
Also  various  independent  Architects  and  Heating  Engineers  having 
wide  experience  in  the  subject. 

465855 


This    broad    endorsement   gives    the  requirements    a   reputation   for 
correctness  which  has  not  been  accorded  to  any  similar  set  of  specifications 
hitherto   prepared.     It  is,    therefore,  hoped    the    Ordinance   may   receive 
generous  public  approval,  and  become  a  construction  standard  in  states, 
cities  and  towns  throughout  the  country.     We  urge  its  adoption. 

National  Board  of  Fire  Underwriters, 

Committee  on  Construction  of  Buildings. 

E.  T.  CAIRNS,  Chairman, 

F.  W.  DAY,  R.  C.  CHRISTOPHER, 

CHAS.  H.  HAHN,  J.  A.  KELSEY, 

JOHN  W.  EMERY,  A.  W.  PERRY, 

E.  G.  PIEPER,  J.  M.  WENNSTROM. 

The   Ordinance   was   drafted   for   the  Committee   by  its   Consulting 
Engineer,  to  whom  correspondence  in  reference  to  same  should  be  sent. 

Address 

IRA  H.  WOOLSON,  Consulting  Engineer, 
National  Board  of  Fire  Underwriters, 

76  William  Street,  New  York  City. 


Should  copies  of  the  Plates  used  in  the  Ordinance  be  desired  they  will 
be  furnished  at  the  cost  of  duplicating  the  electrotypes. 


AN  ORDINANCE 

Providing  Minimum  Requirements   for  Proper  and 
Safe  Construction  of  Chimneys,  Flues  and  Fireplaces  in 

the of 

Scope  of  the  Ordinance. 

This  Ordinance  does  not  apply  to  chimneys  for  high  pres- 
sure boilers,  furnaces  used  in  manufacture,  or  for  other  heating 
appliances  where  high  temperatures  are  maintained;  but  shall 
apply  to  all  other  chimneys  which  form  a  part  of  a  building  con- 
struction. 

Section  I.     Chimney  Construction. 

1.  The  walls  of  all  chimneys  to  which  this  Ordinance  ap- 
plies, whether  the  fuel  used  be  wood,  coal,  gas  or  oil,  shall  be 
built  of  brick,  concrete,  stone,  or  hollow  tile,  of  such  thickness 
and  construction  as  is  hereafter  specified,  but  this  shall  not  pre- 
clude the  use  of  a  metal  smoke-stack  when  located  inside  of  a 
vent  shaft  having  walls  not  less  than  8  inches  thick,  and  having 
an  air  space  between  the  walls  and  stack  on  all  sides. 

2.  Brick  chimneys  shall  be  built  of  solid  brick,  or  may  be 
built  of  perforated  radial  brick  manufactured  for  the  purpose 
and  adapted  to  withstand  high  temperatures,  but  no  other  hollow 
brick  shall  be  used. 

3.  The  walls  of  brick  chimneys  shall  be  not  less  than  3^4 
inches  thick  (width  of  a  standard  size  brick),  and  shall  be  lined 
with  fire  clay  flue  lining. 

4.  Flue  lining  may  be  omitted  in  brick  chimneys  for  private 
dwellings  provided  the  walls  of  the  chimneys  are  not  less  than 
8  inches  thick,  and  that  the  inner  course  shall  be  a  refractory 
clay  brick  having  a  softening  point  of  at  least   1922  degrees 
Fahrenheit  (Seger  Cone  05).    See  Appendix  I  and  II. 

5.  Perforated  radial  brick  chimneys  may  be  unlined,  pro- 
vided the  brick  shall  have  a  softening  point  of  not  less  than  1994 
degrees  Fahrenheit  (Seger  Cone  03),  and  shall  be  not  less  than 

3 


7^2  inches  in  radial  thickness,  except  that  when  such  chimney 
is  located  inside  a  vent  shaft  having  walls  not  less  than  8  inches 
thick,  the  thickness  of  the  chimney  wall  may  be  determined 
by  engineering  design.  The  brick  shall  be  shaped  to  the  circular 
and  radial  lines  of  the  various  sections  of  the  shaft  so  as  to  form 
even  joints. 

6.  All  brick  work  shall  be  laid  in  spread  mortar,  with  all 
joints  push-filled.     Exposed  joints  both  inside  and  outside  shall 
be  struck  smooth.     No  plaster  lining  permitted. 

7.  Concrete  chimneys  cast  in  place  shall  be  suitably  rein- 
forced vertically  and  horizontally.     The  walls  shall  be  not  less 
than  334  inches  thick  and  shall  be  lined  with  fire  clay  flue  lining. 

Flue  linings  may  be  omitted  in  reinforced  concrete  chimneys 
for  private  dwellings,  provided  the  walls  of  the  chimneys  be 
not  less  than  6  inches  thick,  and  provided  further  that  quartz 
gravel  shall  not  be  used  as  the  coarse  aggregate.  See  Ap- 
pendix III. 

8.  Concrete  blocks  used  in  chimney  construction  shall  have 
walls  not  less  than  334  inches  thick,  and  blocks  enclosing  more 
than  one  flue  shall  have  suitable  reinforcement  completely  en- 
circling the  blocks  and  well  embedded  in  them.     All  concrete 
block   chimneys   shall  have   fire   clay  flue   lining.     See   Appen- 
dix III. 

9.  Stone  chimneys  shall  be  at  least  4  inches  thicker  than 
required  for  corresponding  brick  chimneys,  and  shall  have  fire 
clay  flue  linings.     Rubble  stone  chimney  walls  shall  be  not  less 
than  12  inches  thick. 

10.  Hollow  building  tile  shall  not  be  used  for  the  walls  of 
isolated  or  independent  chimneys,  but  may  be  used  for  chimneys 
built  in  connection  with  exterior  hollow  tile  walls  of  buildings 
not  exceeding  three  stories  in  height,  in  which  case  the  chimney 
walls  shall  be  not  less  than  8  inches  thick.     The  outer  8  inches 
of  a  building  wall  may  serve  as  the  outside  wall  of  the  chimney, 
but  the  remaining  chimney  walls  shall  be  constructed  of  two  layers 
of  4-inch  tile  set  with  broken  joints ;  or  they  may  be  built  of  4 
inches   of   solid  brickwork.     In   either   case   the   walls  of   the 


chimney  shall  be  securely  bonded  into  the  wall  of  the  building. 
No  chimney  shall  be  corbeled  from  a  hollow  tile  wall.  All  chim- 
neys built  of  hollow  building  tile  shall  have  fire  clay  flue  lining. 
See  Appendix  IV. 

11.  Chimneys  shall  be  built  at  least  3  feet  above  flat  roofs, 
and  2  feet  above  the  ridges  of  peak  roofs,  and  shall  be  properly 
capped  with  stone,  terra  cotta,   concrete,   cast  iron,  or  other 
approved  material ;  but  no  such  cap  or  coping  shall  decrease  the 
required  flue  area.     See  Plates  I  and  II. 

12.  Fire  clay  flue  linings  shall  be  manufactured  from  suit- 
able refractory  clay,  either  natural  or  compounded,  which  has  a 
softening  point  not  lower  than  1994  degrees  Fahrenheit  (Seger 
Cone  03),  and  shall  be  adapted  to  withstand  high  temperatures 
and  flue  gases.     They  shall  be  of  standard  commercial  thickness, 
but  not  less  than  £4  inch.     The  flue  sections  shall  be  set  in  mortar 
of  quality  hereafter  specified  and  shall  have  the  joints  struck 
smooth  on  the  inside.     The  masonry  shall  be  built  around  each 
section  of  lining  as  it  is  placed,  and  all  spaces  between  masonry 
and  linings  shall  be  completely  filled  with  mortar.     No  broken 
flue  lining  shall  be  used.     Flue  linings  shall  start  at  least  4  inches 
below  the  bottom  of  smokepipe  intakes  of  flues,  or  from  the 
throats    of    fireplaces,    and    shall    be    continuous    the    entire 
heights    of    the    flues    and    project    at    least    4    inches  above 
chimney  top  to  allow  for  a  2  inch  wash  and  a  2  inch  projection  of 
lining.     The  wash  or  splay  shall  be  formed  of  a  rich  cement 
mortar.    To  improve  the  draft  the  wash  surface  should  be  con- 
cave wherever  practical.    Instead  of  the  wash,  a  special  chimney 
cap  or  coping  may  be  used.     Wherever  flue  linings  are  specified 
fire  brick  may  be  substituted  if  desired. 

13.  Chimneys  shall  not  rest  upon  or  be  carried  by  wooden 
floors,  beams  or  brackets,  nor  be  hung  from  wooden  rafters. 
Iron  brackets  or  stirrups  attached  to  wooden  construction  shall 
not  be  used  to  support  chimneys.     In  frame  buildings  chimneys 
shall  always  be  built  from  the  ground  up,  or  rest  on  basement 
walls. 

14.  Chimneys   shall   be   built   upon   concrete   or   masonry 
foundations  properly  proportioned  to  carry  the  weight  imposed 

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JEQTION         '& 

PLATE  I. 

Elevation  and  section  of  an  interior   independent  chimney  showing 
recommended   construction.     Extra   flues   can   be   added   as   desired. 


without  danger  of  settlement  or  cracking.     The  foundation  for 
an  exterior  chimney  shall  start  below  the  frost  line. 

15.  The  walls  of  brick  buildings  may  form  part  of  a  chim- 
ney, but  the  walls  of  the  chimney  shall  be  securely  bonded  into 
the  walls  of  the  building,  and  the  flue  shall  be  lined  the  same 
as  an  independent  chimney.     Flues  in  party  walls  shall  not  ex- 
tend beyond  the  center  of  the  walls,  and  their  location  shall  be 
permanently  indicated  on  the  exposed  side  of  the  wall. 

16.  No  wall  less  than  12  inches  thick  shall  be  used  to  sup- 
port a  corbeled  chimney;  such  corbeling  shall  not  project  more 
than  6  inches  from  the  face  of  the  wall,  and  in  all  such  case? 
the  corbeling  shall  consist  of  at  least  five  courses  of  brick. 

17,  Flues  shall  be  built  as  nearly  vertical  as  possible,  but  in 
no  case  shall  they  have  an  angle  greater  than  45  degrees  from 
the  vertical.  Where  flues  change  direction,  the  abutting  linines 
at  the  angle  joints  shall  be  chipped  to  fit  closely,  and  at  no  point 
shall  the  cross  section  area  be  reduced.  There  shall  be  but  one 
connection  to  a  flue. 

18.  Not  more  than  two  flues  shall  be  permitted  in  the  same 
flue  space,  and  the  joints  of  any  two  adjoining  sets  of  flue  lin- 
ings shall  be  offset  at  least  7  inches.     When  there  are  more 
than  two  flues  in  a  chimney,  at  least  each  third  flue  shall  be  separ- 
ated from  the  others  by  a  smoke-tight  withe  or  division  wall  of 
brick  or   concrete   at   least   3^4    inches  thick   and  bonded   into 
the  sidewalls.     Each  flue  intended  for  a  heating  furnace  or  boiler 
connection,  or  for  a  fireplace,  shall  be  separated   from  other 
flues  by  such  a  withe.     In  hollow  tile  chimneys  the  withe  may 
be  of  tile.     See  Appendix  V. 

19.  When  any  single  flue  area  within  chimney  walls  exceeds 
200  square  inches,  the  walls  shall  be  built  not  less  than  8  inches 
thick  and  shall  have  fire  clay  flue  lining  as  previously  specified, 
but  when  flues  become  so  large  as  to  render  it  impractical  to 
secure  fire  clay  flue  lining,  they  shall  be  lined  with  fire  brick  for 
a  distance  of  at  least  25  feet  from  the  point  of  intake.     Fire 
brick  shall  be  laid  in  fire  clay  mortar. 

7 


N6-F-U- 

192.1 


PLATE  II. 

Details  of  chimney  construction  showing  method  of  flashing  at  roof 
surface,  also  a  wash  course,  but  no  cap  surrounding  flues  at  top.  See 
Plate  I. 


20.  Connections  between  chimneys  and  roofs  shall  be  made 
with  sheet  metal  counter  or  cap  flashing  (copper  recommended), 
arranged  to  overlap  roof  flashing  and  allow  for  movement  that 
may  occur  between  chimneys  and  roofs.     See  Plates  I  and  II. 

21.  No  increase  in  the  wall  thickness  of  chimneys,   nor 
any  projecting  masonry,  shall  /be  permitted  within  a  distance 
of  12  inches  above  or  below  the  rafters  or  roof  joists. 

22.  Irrespective  of  whether  the  fuel  used  be  coal,  coke, 
wood,  or  oil,  the  minimum  area  inside  of  chimney  flue  linings  for 
various  heating  devices  shall  be  as  follows :    For  warm  air  fur- 
naces, or  low  pressure  steam  or  hot  water  heating  boilers,  not  less 
than  75  square  inches ;  for  fireplaces,  not  less  than  one-tenth  the 
area  of  the  fireplace  opening,  but  never  less  than  75  square  inches  ; 
for  stoves,  ranges,  and  other  forms  of  room  heaters,  49  square 
inches  for  rectangular  flues,  or  an  inside  diameter  of  7  inches 
for  round  flues.     In  no  case  shall  the  short  cross  section  dimen- 
sion of  a  rectangular  flue  be  less  than  two-thirds  the  greater 
dimension.     See  Appendix  VI. 

When  gas  is  the  fuel  used  in  a  heating  furnace,  boiler,  or 
automatic  hot  water  heater,  the  flues  shall  be  of  the  same  size 
and  construction  as  required  for  stoves  and  ranges  using  other 
fuel.  Vent  flues  where  required  for  other  domestic  gas  burn- 
ing appliances  may  be  of  smaller  size,  but  not  less  than  10  square 
inches.  Such  flues  shall  be  made  of  fire  clay  or  its  equivalent 
not  less  than  1  inch  thick  with  joints  properly  designed  to  effect 
a  permanent  seal,  and  the  surrounding  masonry  walls  may  be 
omitted.  Metal  vent  flues  are  not  permitted. 

23.  Smokepipe  intakes  to  flues  shall  always  enter  the  chim- 
ney through  the  side  and  shall  consist  of  fire  clay  or  metal 
thimbles  securely  set  in  the  chimney  wall  with  mortar,  or  the 
intake  may  be  cast  in  concrete.     Such  openings  shall  be  at  least 
18  inches  below  wooden  lath  and  plaster  or  other  combustible 
ceilings,  or  open  joists.     Neither  the  intake  pipe  nor  thimble 
shall  project  into  the  flue.     No  woodwork  shall  be  placed  within 
6  inches  of  the  thimble.     The  thimble  shall  be  surrounded  by 
metal  lath  and  plaster  for  a  space  of  at  least  6  inches,  or  an  open 
space  of  that  width  shall  be  provided  on  all  sides.     See  detail 
sketch  Plate  I. 


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PLATE  III. 

Fig.  1.— Method  for  building  two  fireplaces  back-to-back 
in  a  brick  party  wall  to  secure  proper  spacing  between  ends  of 
floor  joists. 

Fig.  2. — Floor  framing  around  a  single  fireplace.  Note 
filling  between  framing  and  brickwork,  which  serves  both  as 
insulator  and  fire-stop. 

10 


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METAL  LATH 


Fig.  1. — Floor  framing  around  chimney  in  a  party  wall,  to  secure 
proper  space  between  ends  of  floor  joists. 

Fig.  2. — Ordinary  floor  framing  around  a  chimney.  All  timbers  2 
inches  cl-ear  of  brickwork  and  space  filled  with  fireproofing  material. 

Fig.  3. — Stud  partition  across  back  of  a  chimney  showing  proper 
method  of  arranging  studs. 

Fig.  4. — Stud  partition  across  back  of  a  fireplace  and  around  the  ends 
of  the  chimney  breast,  showing  proper  arrangement  of  studs.  Method 
of  fire-stopping  this  space  is  shown  on  chimney  section,  Plate  I,  also  in 
Fig.  2,  Plate  III. 

11 


24.  All  mortar  used   in  chimney  construction,   except  as 
specified  for  fire  brick  in  paragraph  19,  shall  be  cement  mortar 
proportioned  as  follows :     Two  bags  of   Portland  cement,  not 
less  than   188  pounds,  and  one  bag  of  dry  hydrated  lime,  50 
pounds,  thoroughly  mixed  dry.     To  this  mixture  shall  be  added 
three  times  its  volume  of  clean,  sharp  sand  with  sufficient  water 
to  produce  proper  consistency.    When  dry  hydrated  lime  is  not 
available,    1    cubic  foot   of   completely   slaked   lime  putty   may 
be  substituted  for  50  pounds  of  dry  hydrate.     In  case  of  such 
substitution,    the   mixing    of    lime    and    cement    shall    be   very 
thorough.     Dry  hydrate  should  always  be  used  in  preference  to 
lime  putty. 

25.  After  a  chimney  has  been  completed,  all  flues  shall  be 
thoroughly  cleaned  and  left  smooth  on  the  inside. 

26.  All  flues  to  which  heating  furnaces  or  boilers  are  to 
be  connected  shall  be  subjected  to  a  smoke  test  before  acceptance, 
but  the  test  shall  not  be  made  until  the  mortar  has  thoroughly 
hardened.     The  method  of  test  is  to  build  a  smudge  fire  at  bot- 
tom of  the  flue  and  while  the  smoke  is  flowing  freely  from  the 
flue,  close  it  tightly  at  the  top.     Escape  of  smoke  into  other  flues 
or  through  the  chimney  walls  indicates  openings  that  shall  be 
made  tight  before  the  chimney  is  accepted.     The  test  shall  be 
made  by  the  contractor  in  the  presence  of  the  Building  Inspector 
or  other  official  having  jurisdiction,  and  of  the  owner  or  his 
representative. 

Section  II.     Woodwork  Around  Chimneys. 

1.  No   wooden   beams,   joists,   or   rafters   shall  be  placed 
within  2  inches  of  the  outside  face  of  chimneys,  whether  the  same 
be  for  smoke,  air  or  any  other  purpose.     No  woodwork  shall  be 
placed  within  4  inches  of  the  back  wall  of  any  fireplace.     See 
Plate  III,  Fig.  2,  and  Plate  IV,  Fig.  4. 

2.  All  spaces  between  chimneys  and  wooden  joists  or  beams 
shall  be  filled  with  loose  cinders,  loose  mortar  refuse,  gypsum 
block,   or  other  porous  incombustible  material  to   form  a  fire- 
stop.     See  Plates  I,  III  and  IV. 

12 


The  incombustible  material  shall  be  supported  by  strips  of 
sheet  metal  or  metal  lath  set  into  the  brickwork  and  nailed  to 
the  wooden  beams,  forming  a  buckled  flexible  joint  between,  as 
indicated  in  Plate  I ;  or  by  similar  strips  of  metal  nailed  to 
the  woodwork  with  the  inner  edge  close  to  the  chimney.  See 
Plate  V. 

3.  No  wooden  studding,  furring,  lathing,  or  plugging  shall 
be  placed  against  any  chimney,  or  in  the  joints  thereof.  Wooden 
construction  shall  either  be  set  away  from  the  chimneys,  or  the 
plastering  shall  be  directly  on  the  masonry  or  on  metal  lathing 
or  on  incombustible  furring  material.  Wood  furring  strips  placed 
around  chimneys  to  support  base  or  other  trim  shall  be  insulated 
from  the  masonry  by  asbestos  paper,  at  least  ^6-inch  thick,  and 
metal  wall  plugs  or  approved  incombustible  nail  holding  devices 
attached  to  the  wall  surface  shall  be  used  for  nailing.  See 
Plate  V. 


AS&RTOS  B>OAtk 
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METAL 
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PLATE  V. 

Detail  showing  support  for  fire-stopping  around  chimney, 
and  protection  for  woodwork  placed  next  to  plaster  on  chimney 
brickwork. 

13 


4.  The  walls  of  fireplaces  shall  never  be  less  than  8  inches 
thick,  and  if  built  of  stone  the  minimum  thickness  shall  be  12 
inches. 

5.  All  fireplaces  and  chimney  breasts  shall  have  trimmer 
arches  or  other  approved  fire-resistive  construction  supporting 
hearths.     The  arches   and  hearths   shall  be   at  least  20  inches 
wide  measured  from  the  face  of  the  chimney  breast.    The  arches 
shall  be  of  brick,  stone  or  hollow  tile,  not  less  than  4  inches 
thick.     A  flat  stone  or  a  reinforced  concrete  slab  may  be  used  to 
carry  the  hearth  instead  of  an  arch  if  it  be  properly  supported 
and  a  suitable  fill  be  provided  between  it  and  the  hearth.    The 
length  of  trimmer  arches  and  hearths  shall  be  not  less  than  24 
inches  longer  than  the  fireplace  opening.     Hearths  shall  be  of 
brick,  stone,  tile,  or  concrete  as  may  be  specified.    Wood  center- 
ing under  a  trimmer  arch  shall  be  removed  before  plastering 
the  ceilings  beneath. 

6.  No  coal  burning  heater  shall  be  placed  in  a  fireplace 
which  does  not  conform  to  the  foregoing  requirements  and  have 
an  incombustible  mantel. 

7.  No  wooden  mantel  or  other  woodwork  shall  be  placed 
within  8   inches   of  the  side   or  within    12   inches   of   the   top 
of  any  open  fireplace.     No  combustible  summer  piece  or  fire 
board  shall  be  used. 

8.  Any  person  or  persons,  whether  owner,  builder  or  me- 
chanic, who  shall  build  a  chimney  or  flue  in  violation  of  any 
requirement  of  this  Ordinance  shall  be  deemed  guilty  of  a  mis- 
demeanor and  shall  be  fined  not  less  than  $10  nor  more  than 

$ for  each  offense ;  and  any  chimney  or  flue  which  is  built 

in  violation  of  any  requirement  of  this  Ordinance  shall  be  im- 
mediately demolished  or  rebuilt.     It  shall  be  the  duty  of  the 
Building  Inspector  or  other  duly  authorized  official  to  enforce 
this  Ordinance. 

9.  All  ordinances  or  parts  of  ordinances  in  conflict  with 
this  Ordinance  are  hereby  repealed. 

10.  This  Ordinance  shall  take  effect  upon  being  approved 
by  the 

14 


APPENDIX 

This  Appendix  contains  reasons  for  certain  requirements  in 
the  Ordinance,  and  various  suggestions  for  good  practice  not 
suitable  to  be  included  in  the  Ordinance  itself,  but  which  are 
thought  to  be  useful  information  to  accompany  it.  The  material 
is,  therefore,  appended  for  its  educational  value,  and  a  munici- 
pality in  adopting  the  Ordinance  can  dispose  of  the  Appendix 
as  it  sees  fit. 

I.  Heat  Resistance  of  Brick. 

Brick  meeting  the  temperature  requirement  of  Section  I, 
paragraph  4,  of  the  Ordinance  can  be  obtained  in  all  sections  of 
the  country  at  a  slight  cost  above  that  of  ordinary  brick.  In  sev- 
eral regions  the  ordinary  brick  of  the  market  will  meet  the  re- 
quirement, and  in  such  places  there  would  be  no  additional  cost. 

It  is  suggested  that  each  manufacturer  of  flue  linings  or 
heat  resisting  brick  suitable  for  chimney  lining  should  have  tests 
made  of  the  softening  point  of  the  clays  used  in  the  manufacture 
of  such  products.  Such  tests  should  be  made  by  a  laboratory 
of  recognized  standing,  and  the  test  certificate  would  constitute 
the  authority  for  acceptance  of  the  product  as  fulfilling  the  re- 
quirements, provided  suitable  identification  marks  were  placed  on 
the  material.  This  would  be  a  simple  method  of  accomplishing 
the  object,  and  the  quality  of  clay  from  any  particular  bank  is 
sufficiently  uniform  to  secure  reliable  results. 

II.  Thickness  of  Exterior  Chimney  Walls. 

For  exterior  chimneys,  or  chimneys  having  any  wall  exposed 
to  the  weather,  it  is  recommended  that  all  such  exposed  walls  be 
not  less  than  8  inches  thick  even  though  lined.  This  additional 
thickness  will  produce  a  more  uniform  temperature  in  the  flue, 
thereby  greatly  improving  the  draft,  which  will  result  in  fuel 
economy  and  a  lessening  of  smoke  annoyance. 

III.  Concrete  Chimneys. 

Pure  quartz  gravel  or  other  highly  silicious  gravel  con- 
cretes are  not  adapted  to  withstand  high  temperatures,  there- 
fore should  not  be  used  where  subject  to  direct  attack  of  heat. 

15 


APPENDIX 

The  reinforcement  required  in  concrete  chimneys  cast  as  a 
unit,  or  when  built  of  large  blocks  enclosing  more  than  one  flue 
is  to  resist  stresses  due  to  temperature  variations  or  unequal 
settlement  of  foundations. 

IV.  Filling  of  Hollow  Building  Tile. 

When  chimney  walls  are  built  of  hollow  tile  as  provided 
in  Section  I,  paragraph  10,  it  is  recommended  that  the  inner  course 
of  cells  next  to  the  flue  lining  be  filled  with  mortar. 

V.  Withes. 

A  withe  between  at  least  every  second  and  third  flue 
in  a  chimney  space  is  strictly  necessary  to  insure  stability  of 
the  chimney.  A  withe  also  aids  in  securing  uniform  tempera- 
ture in  a  flue,  and  prevents  air  leakage,  thus  promoting  good 
draft  and  fuel  economy.  At  the  same  time  it  prevents  possibility 
of  a  fire  in  one  flue  communicating  to  the  others.  For  these 
reasons  every  flue  connected  with  a  fireplace  or  heating  furnace 
of  any  type  is  required  to  be  separated  from  other  flues  by  such 
withes.  The  ideal  chimney  would  have  all  flues  separated  by 
withes.  See  Plate  IV. 

VI.  Area  and  Heights  of  Chimneys 

To  secure  the  most  satisfactory  draft  conditions,  the  area 
and  height  of  a  chimney  should  be  proportional  to  the  size 
and  character  of  heating  appliance  attached  to  it.  A  poor  draft 
is  a  great  annoyance,  and  is  difficult  to  remedy  after  a  chimney 
is  built. 

A  round  flue  will  give  a  better  draft  than  a  square  or  other 
rectangular  shape  having  the  same  cross-sectional  area.  Round 
flues  are  recommended  where  it  is  practical  to  obtain  them,  but. 
when  round  flue  linings  are  placed  inside  rectangular  chimney 
walls,  care  must  be  exercised  to  insure  complete  filling  of  the 
corner  spaces,  otherwise  there  is  liable  to  be  air  leakage  into  the 
vacant  spaces,  which  injures  the  draft  and  increases  the  fire 
hazard. 

The  following  Table  gives  the  approximate  area  and  height 
of  chimneys  recommended  by  the  furnace  and  boiler  manufac- 

16 


APPENDIX 


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APPENDIX 

turers  associations  as  suitable  to  produce  proper  draft  for  heat- 
ing equipment  of  different  kinds  and  varying  sizes  when  coal 
or  coke  is  the  fuel  used. 

The  American  Institute  of  Architects  and  the  American 
Society  of  Heating  and  Ventilating  Engineers  have  withheld 
approval  of  this  Table  on  the  ground  that  it  is  not  yet  a  suffi- 
ciently recognized  standard  to  warrant  its  being  accepted  as  a 
satisfactory  guide  in  all  cases.  The  other  endorsers  of  the 
Ordinance  have  not  expressed  an  opinion  on  this  matter. 

VII.     Suggestions  for  Repair  of  Old  Unlined  Chimneys. 

1.  A  chimney  in  any  existing  building  that  becomes  too 
hot  to  hold  the  hand  against  comfortably  is  dangerous  if  there 
is  woodwork  touching  it.     Have  it  carefully  inspected  by  a  re- 
liable   mason,    and    apply    the    protection    prescribed    by    this 
Ordinance  as  far  as  is  possible. 

2.  The  smoke  test  as  described  in  Section  I,  paragraph  26,  is 
strongly  recommended  as  the  best  method  for  discovering  defects 
in   chimney   walls   which    always    indicate    danger.      If   smoke 
escapes  through  the  chimney  walls  at  any  place  the  chimney 
should  be  repointed  or  rebuilt  as  conditions  may  warrant. 

3.  Where  soft  coal  is  used  it  is  often  necessary  to  rebuild 
unlined  chimney  tops  every  few  years,  and  all  unlined  chimneys, 
irrespective  of  fuel  used,  are  very  liable  to  become  defective 
through  disintegration  of  the  mortar  joints.    In  order  to  ascertain 
if  chimneys  need  rebuilding,  climb  to  the  top  and  look  inside. 
If  mortar  has  begun  to  fall  out  from  between  the  bricks  it  will 
soon  do  so  all  the  way  through  the  wall.     Take  an  ice  pick,  a 
table  knife,  or  other  sharp  implement  and  try  to  push  it  through 
the  mortar ;  if  you  can  do  so,  rebuild  at  once  as  follows : 

Tear  the  chimney  down  to  a  point  where  mortar  joints  are 
solid,  but  at  least  18  inches  below  the  roof,  get  fire  clay  flue 
lining  of  the  same  size  as  the  inside  measurement  of  the 
chimney,  set  it  in  the  top  of  the  flue  and  build  up  with  good 
brick  and  Portland  cement  mortar.  This  will  make  a  solid 
chimney  through  the  roof  where  there  is  greatest  danger,  and 
is  the  best  that  can  be  done  unless  the  chimney  is  completely 

18 


APPENDIX 

torn  down  and  rebuilt.  Preserve  a  clear  space  of  at  least  1  inch 
between  the  woodwork  of  the  roof  and  the  chimney  wall,  and 
connect  the  chimney-  with  the  roof  by  metal  flashings.  Build  to 
a  height  above  the  roof  as  specified  in  Section  I,  paragraph  11, 
of  the  Ordinance. 

VIII.     Cleaning  Chimney  Flues." 

'For  efficient  and  safe  operation  of  heating  apparatus  it  is 
extremely  important  that  both  the  flue  and  the  smoke  passages 
in  the  heating  device  be  free  from  soot.  When  bituminous  coal 
is  used  for  fuel,  soot  accumulates  quite  rapidly  and  frequent 
.cleanings  are  necessary. 

Accumulation  of  soot  in  a  chimney  introduces  the  risk  of  a 
chimney  fire  with  the  consequent  danger  of  sparks  being  thrown 
upon  the  roof  or  penetrating  cracks  in  the  chimney  walls.  This 
is  a  very  great  hazard  and  is  the  reason  why  chimneys  should 
never  be  purposely  burned  out  to  clean  them.  The  burning  out 
of  a  tile  lined  flue  is  liable  to  crack  the  lining. 

A  common  and  efficient  method  of  cleaning  a  chimney  is  to 
sweep  it  with  a  properly  weighted  bundle  of  rags  or  a  bush  at- 
tached to  a  rope  and  worked  from  the  top,  but  because  this 
operation  is  troublesome,  chimney  cleaning  is  frequently  neg- 
lected. 

Other  methods  of  chimney  cleaning  recommended  as  simple 
and  efficient  are  as  follows: 

1.  The  U.  S.  Fuel  Administration  has  strongly  advocated 
the  use  of  salt.  The  fire  should  be  put  in  good  condition  with  a 
substantial  body  of  hot  fuel.  Well  dried  common  salt  is  then 
scattered  over  the  incandescent  fuel  in  quantity  depending  upon 
the  size  of  the  furnace.  For  a  household  furnace,  a  pound  at  a 
time  is  ample.  The  dampers  should  be  kept  open  to  maintain 
the  furnace  temperature  until  the  fumes  entirely  disappear. 
This  usually  takes  about  half  an  hour.  The  soot  is  disintegrated 
by  the  action  of  the  salt  fumes.  Repeat  the  application  as 
necessary. 

This  method  is  highly  endorsed  for  cleaning  boiler  tubes 
and  furnace  passages.  It  does  not  interfere  with  the  operation 
of  the  plant  and  neither  brickwork  nor  metal  is  deteriorated. 

19 


APPENDIX 

It  is  known  that  a  layer  of  tarry  soot  1/16  inch  thick  on 
boiler  tubes  or  furnace  passages  will  decrease  their  heating 
efficiency  20  per  cent,  hence  the  necessity  of  keeping  them  clean. 
It  is  claimed  that  an  occasional  use  of  salt  as  described  will  keep 
both  heating  apparatus  and  flue  free  from  soot. 

2.  An   ex-fire  chief   recommends   firing  a  revolver  loaded 
with  one  or  two  blank  cartridges  up  a  chimney  flue  to  remove 
soot.     He  asserts  it  to  be  very  effective  and  that  no  injury  to 
the  flue   results.     Precaution   should  be  taken  to   shut   off  the 
flue  opening  or  fireplace  with  an  old  blanket  or  piece  of  burlap 
to  prevent  the  soot  flying  back  into  the  room  when  it  falls  fol- 
lowing the  shot.     This  method  requires  that  the  fires  be  ex- 
tinguished before  it  is  applied. 

3.  Scrap  zinc  thrown  on  a  hot  fire  is  recommended  as  a 
soot  remover.    The  zinc  fumes  are  said  to  disintegrate  the  soot. 

Zinc  compounds  are  also  sold  for  this  purpose,  but  as  several 
pounds  of  these  zinc  materials  are  recommended  to  be  used  at  a 
time,  they  would  be  somewhat  expensive. 

IX.     Extinguishing  Chimney  Fires. 

A  handful  or  two  of  powdered  sulphur  thrown  on  a  fire  is 
claimed  to  be  effective  in  extinguishing  a  soot  fire  in  a  chimney.  It 
produces  sulphur  dioxide  which  extracts  the  oxygen  from  the 
air  supply  and  so  prevents  combustion. 

A  few  pounds  of  salt  thrown  in  the  flue  at  the  top  is  an  old 
and  excellent  remedy  for  a  soot  fire.  Even  a  pail  of  sand  earth 
or  ashes  is  helpful.  Such  materials,  however,  should  be  used 
with  much  care,  if  at  all,  when  a  fireplace  connects  with  the 
chimney  flue,  for  they  would  be  liable  to  scatter  the  burning  soot 
into  the  room  where  the  fireplace  is  located. 


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